I am building a GPIO module that actually powers the Raspberry Pi. I am working with Pi 3B boards and want to feed power directly to GPIO pins 2/4 (VCC +5V) and pin 6 (GND,) completely bypassing the micro USB port to save materials cost and complexity.
Is this allowed or is GPIO power only 1-way? I really don't want to fry a board finding out the hard way.
Thanks.